Clear viewing screens

ABSTRACT

A clear viewing screen for vehicles, particularly for vehicles which have to operate under polar conditions, comprising a fixed screen element, a rotatable disc like screen element mounted in front of the said fixed screen element with the interposition of a labyrinth joint at the periphery of the said rotatable screen element, a motor for driving the said rotatable screen element, a motor for driving the said rotatable screen element, and electric heating elements in the chamber between the fixed screen element and the rotatable screen element. Means are also provided on the outer surface of the rotatable screen element for breaking the ice crusts formed on said screen element, and operated by the rotatable screen element driving motor.

United States Patent Speich 1451 Aug. 29, 1972 [54] CLEAR VIEWINGSCREENS 72 Inventor: Pier Gianni Speich, f7/c Via Domenico Chiodo,Genoa,ltaly 22 Filed: Nov. 9, 1970 21] App1.No.: 87,766

30 11 11 66 11 Priority Data Nov. 12, 1969 m ..-.....7439 A/69 52 US.Cl. ..219/203, 15/25005, 52/171,

51 int. c1. ..E06b 3/12, 0515 3/00 [58] Field or Search ..350/61, 62,-63; 52/171, 172; 296/84 H; 219/203, 522; 15/250.05

56 References Cited UNITED STATES PATENTS 2,383,750 8/1945 Smith..52/171 1,378,604 5/1921 Murphy ..219/203 x 3,188,700 6/1965 Herrmannet a1 ..52/171 3,347,004 10/1967 Allen ..52/171 3,429,086 2/1969 Speich..52/171 3,495,366 2/1970 Allen ..350/62 ux 3,045,551 7/ 1 962 Bonanno..350/62 FOREIGN PATENTS on APPLICATIONS 900,916 7/1962 Great Britain..52/171 Primary ExaminerA. Bartis I Attorney-Edwin E. Greig'g 7]ABSTRACT A clear viewing screenforvehicles, particularly for vehicleswhich have to operate under polar conditions, comprising a fixed screenelement, a rotatable disc like screen element mounted in front of thesaid fixed screen element with the interposition of a labyrinth joint atthe periphery of the said rotatable screen element, a motor for drivingthe said rotatable screen element, a motor-for driving the saidrotatable screen element, and electric heating elements in the chamberbetweenthe fixed screen element and the rotatable screen element. Meansare also provided on the outer surface of the rotatable screen elementfor breaking the ice crusts formed on said screen element, and operatedby the rotatable screen element driving mo tor.

5Claims,2DrawingFigures ICE CRUST 825A KER CLEAR vmwmc SCREENSBACKGROUND OF THE INVENTION This invention relates to clear viewingscreens for vehicles, and particularly for ships, motor boats, airplanes and other vehicles, which comprises two parallel screen elementsof transparent material, one of which is rotatable so as to throw off,by centrifugal action, any water or other material which might otherwiseaccumulate thereon.

The invention is an improvement over existing clear viewing screens ofthis kind and aims to provide means for preventing the formation of, andfor eliminating the ice crusts from the said rotatable screen element,which may form on said screen whenever same is exposed to very lowtemperatures, as may for instance be the case in vessels exposed topolar conditions or the like. 7

SUMMARY OF THE INVENTION According to the invention, a clear viewingscreen of the type described is characterized in that in the spacebetween the rotatable screen element and the fixed screen element atleast one annular electric heating element is disposed. The said heatingelement is advantageously disposed centrally around the axle of therotatable screen element. A second heating element may be also provided,in the space between the rotatable screen element and the fixed screenelement, in the outer peripheral zone of the said space.

According to a further improvement of the invention, means may beprovided, operated by the same electric motor driving the rotatablescreen element, for breaking the ice crusts formed on the external sideof the rotatable screen element. According to one preferred embodimentof the invention, the said means are in the form of a cap reciprocatedrelative to the outer surface of the rotatable screen element by armsslidable along the outer surface of the rotatable screen, and operatedthrough a' cam transmission by the shaft of the rotatable screen drivingmotor.

Further improvements and characteristic features of the invention willbe apparent from the following specification and will be pointed out inthe appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a cross-sectional sideelevation showing the clear viewing screen of the invention in positionin a windscreen, and

FIG. 2 is a front view of the clear viewing screen of FIG. 1, with partsbroken away.

DESCRIPTION OF THE PREFERRED EMBODIMENT With reference to the figures ofthe drawings, 3 is a windshield glass section of a vehicle, in front ofthe pilot or the driver.

In front of the said windshield section 3, a centrally perforatedtransparent disc 6 is rotatably mounted by being inserted upon, andfastened by means of a sleeve to a bell shaped extension 4 of the shaft101 of an electric motor I mounted in a hole of the window glass 3. Tothis end, the motor casing l is provided with an abutment collar 102 andis inserted into the glass hole by its end opposite to the motor shaftuntil said abutment 102 abuts against said glass 3. The motor 1 isfastened to the windshield by means of a conventional screw-threadedlocking ring 2.

The disc 6 is provided at its periphery with a substantially U-shapedrim 7 forming a rotatable member of a labyrinth joint whose wings engagein corresponding annular recesses of the complementary fixed labyrinthjoint member 8 fastened by means of an annular flange 9 and bolts 109 ina corresponding position to the glass 3. This assembly is so constructedand arranged as to form between glass 3 and disc 6 a gap or chamber 10closed at its periphery by a labyrinth joint and at its outer side byadisc 6, which may be rapidly rotated by the motor shaft 101, thuseliminating by centrifugation any condensate, brine or splash waterwhich may come into contact therewith.

The problem arises in clear viewing screens of the kind describedwhenever same have to be used under very low temperature conditions,such as it may be encountered in arctic regions, causing the water whichmay come into contact with the said screens to rapidly freeze in form ofan ice crust adhering to the rotatable screen element, which crust maynot be throw off by simply centrifugation.

According to the invention, in the chamber 10 an electric heatingelement in the form of an annular element 12 is disposed centrally ofthe chamber, around the motor casing l. The heating element 12 issecured in place by means of securing members 14 to the abutment member102. v

A second annular electric heating element 11 is also disposed in chamber10, at the outer periphery of said chamber 10, and is secured by meansof the securing members 13. The said two heating elements are disposedso as to not interfere with the visual field through the clear viewingscreen. The said heating elements are connected, through suitableelectrical leads to a source of current, not shown.

a The heating of the electrical heating elements promotes the detachmentof the ice crust from the screen 6, so that same may be easily throw offby centrifugal action.

In order to facilitate the slipping of the ice crusts from the surfaceof the-rotatable screen element 6, the outer surface 107 of theperipheral rim 7 is slightly stepped down with respect to the outersurface 106 of the screen element 6.

According to a further feature of the invention, means are provided forbreaking the ice crust adhering to the outer surface of the screenelement 6. To this end, around the sleeve 5 a number of radiallyextending arms 18 are provided, these arms each being provided at oneend with a pin 19 slidably engaged into a corresponding hole formed inthe sleeve 5. A cam like member 15 is secured to the fixed motor casingl, and cooperates with a number of pins 16, slidably guided into acorresponding number of holes bored through the bell shaped extension 4and the sleeve 5, in a position corresponding to the arms 18.

A cap 20, made of insulating elastic material, like plastic material isarranged on the sleeve 5, above arms 18.

In this manner, upon rotation of motor shaft 101, the pins 16 areentrained into rotation by bell 4 and sleeve 5, and are caused to slideinside of borings 17 by the action of the cam 15. In this manner themovement of the pins 16 is transmitted to 'the arms 18, and therefrom tothe cap flexible 20, thus providing for flexing of the cap for thebreakage of the ice crusts adhering to the surface 106 of the screenelement 6. It is believed to be clear that the arms 18 deflect theterminus of the wall of the cap back and forth so that the icefracturing action is thereby achieved.

Thus, it will be seen that the utility is further enhanced by the icefracturing means.

The invention is not restricted to the embodiment described above, andpermits of several, structurally different solutions without departingfrom its principle.

Whatl claim is:

1. A clear viewing screen of the kind comprising a fixed screen element,a rotatable disc like screen element, a joint member between said fixedscreen element and the periphery of said rotatable screen elemeritdefining a chamber between said two screen elements and said jointmember, an electric motor having motor driving the rotatable screenelement for breaking the ice crusts which might be formed on the outersurface of said rotatable screen element.

2. A clear viewing screen according to claim 1, in which said ice crustbreaking means comprises a cap made of heat insulating material mountedon said motor shaft, and rotatable means driven by the said motor shaftfor imparting a movement to said cap with respect to said rotatable discscreen element, the outer rim of said cap being incontact with the outersurface of the said screen element.

3. A clear viewing screen according to claim 2, in which the saidrotatable means comprises a cam member, a number of radial pinsguided'into corresponding holes formed into a part solid with the motorshaft, and a corresponding number of arms pivotably connected to thesaid part connected to said motor shaft 4. A clear viewing screen asclaimed in claim 1, wherein the electric heating means includes at leastone annular electric heating element;

5. A clear viewing screen'as claimed in claim 1, wherein the electricheating means includes concentrically disposed annular elements.

1. A clear viewing screen of the kind comprising a fixed screen element,a rotatable disc like screen element, a joint member between said fixedscreen element and the periphery of said rotatable screen elementdefining a chamber between said two screen elements and said jointmember, an electric motor having its shaft connected to said rotatabledisc screen element, for driving said disc screen element, electricheating means in the chamber between said two screen elements, and meansreciprocated relative to the outer surface of the rotatable screen bythe said electric motor driving the rotatable screen element forbreaking the ice crusts which might be formed on the outer surface ofsaid rotatable screen element.
 2. A clear viewing screen according toclaim 1, in which said ice crust breaking means comprises a cap made ofheat insulating material mounted on said motor shaft, and rotatablemeans driven by the said motor shaft for imparting a movement to saidcap with respect to said rotatable disc screen element, the outer rim ofsaid cap being in contact with the outer surface of the said screenelement.
 3. A clear viewing screen according to claim 2, in which thesaid rotatable means comprises a cam member, a number of radial pinsguided into corresponding holes formed into a part solid with the motorshaft, and a corresponding number of arms pivotably connected to thesaid part connected to said motor shaft.
 4. A clear viewing screen asclaimed in claim 1, wherein the electric heating means includes at leastone annular electric heating element.
 5. A clear viewing screen asclaimed in claim 1, wherein the electric heating means includesconcentrically disposed annular elements.